Centering for tunnels



(No Model.) 2 Sheets-Sheet 1.

J. MQNAMARA. GBNTERING FOR TUNNELS.

Y. No. 521,767. r Patented June 19, 1894.

Mfnesses (No Model.) 2 Sheets-Sheet 2. J. MGNAMARA.

GENTERING FOR TUNNBLS.

No. 521,767. Patented June 19, 1894.

FLA 75' 2 m: NATIONAL umusrurnma COMPANY WASHINGTON. Die.

ITO

To all whom it may concern:

PATENT JAMESMCNAMARA, OF SEATTLE, WASHINGTON.

CENTERING FOR TUNNELS.

SPECIFICATION forming part of Letters Patent N o. 521,767,' dated June 19, 1894. Application filed March 15, 1893- Serial No. 466,184. (No model.)

3e it known that 1, JAMES MCNAMARA, a. OltlZBD of the United States, residing at the clty of Seattle, in the county of King and State of Washington, have invented a new and useful rib to be used in and to facilitate the construction of tunnels, sewers, or any like underground Work, open or closed, or in the construction of arches inany place or in any form whatever, of which the following is a specification.

, My invention relates to an improved form of supporting rib for the false work upon whlch the arch portion of sewers, tunnels and similar masonry work is constructed.

It consists essentially of sections so shaped that when puttogether they will form anarch similar. in shape to the masonry arch to be built, but enough smaller to allow of placing the planks which fornfthe lagging, outside thereof which lagging forms the immediate support of the masonry. These sections are so constructed that they may bequickly removed when the masonry. arch is completed without injuring them, and may be used again in another place. 1'

Figure 1 is a perspective View of the ribs in position part of the lagging being in position, the space at the top through which the back filling or packing is done being without its lagging. Fig. 2 is an end elevation, showingone of the ribs in place and the arch nearly completed. Fig. 3 is an inside view of the rib and lagging in place. "Fig. 4: shows the rib as being placed in position. Fig. 5 shows the different sections of the ribs removed. Figs. 6, 7 and 8 show arches of other form than circular and the adaptation of my rib to their construction.

In the construction of this kind of work, the invert would first be laid, and the bottom piece 12 laid centrally thereon. This bottom piece is preferably shaped to fit the invert on the bottom and to be horizontal on the top, and if it is necessary to provide for drainage, it may have a sufficient hole or notch on its under edge to provide therefor, as shown at i in Fig. 2.v The'pieces 11 and 13 are then placed upon either side, having their ends against the ends of the bottom piece. These bring the rib up to or near the point where the arch commences and it is necessary to side'of them will make the exact size of this inner surface. These sections are long enough so that together they reach from the upper end of one of the pieces 11 or 13, to the center of the arch. Two similarly construct-' led pieces 14 and 15, are placedupon the other side, thus completing the rib. Where the two sections come together at the center of the arch they are provided with tenons or dowels to hold them together and prevent slipping.

Except at the upper ends of the pieces 11 and 13, the joints between the sections are radial, ,7

so that they form an arch. In order that the sections may be readily taken down after the masonry arch is completed, and without inj uring the sections, I have made these joints so that-the sections 10 and 14 will have no difficulty in swinging clear of the sections upon which they rest when swung upon the hinges which connect them to the upper sections, the upper sections being in the meanwhile supported. To make the rib firm atthis point and prevent slipping while in use, I

have fixed tothe upper of the two sections an iron plate 0, which fits upon the inner edge of the lower section, and has a slot or hole in its lower end. This slotor hole fits over a bolt, 01, which passes through or is embedded in the lower section. These are then secured together by screwing the nut upon the bolt. The adjacent ends of these two sections may be protected by iron plates,

as shown at h. When the ribs have been placed the lagging is placed outside of them as it is needed, and the masonry arch built thereon. When the arch is completed the nuts 6 upon the bolts (1 are removed, and the section above it swung inward, and the rib is then easily taken apart and removed, and is ready for use again elsewhere. The lower section 12, may be left in place and used as a support for the rails for the cars, or replaced by ties as desired.

In using my invention back-filling may be carried on as the work progresses, but I prefor to carry the work up until a space from eighteen to twenty-four inches, or sufficient to permit a mans working therein, remains at the top of the arch, to be completed. The filling material may then be brought in cars and the filling put in place and tamped as high as it is possible or convenient, and the arch then completed by using short lagging which will reach only from one rib to the next, and the space left above the center of the arch filled from the end. This can be readily done, as the ribs would be onlya short distance apart, ordinarily about four feet. The hinging in the manner shown, of the two sections reaching from the arch to its center, prevents the center of the temporary arch formed by the rib from being raised by the weight of the masonry, as might be done were they not so connected.

This improved form of supporting rib and the method of placing the tunnel lining here- Ill described, makes the construction of such work much cheaper and more speedy. The false work upon which the masonry is constructed does not occupy the space so as to prevent cars from being run through, and when the masonry is completed it may be readily removed without injuring it, and is quickly set up again. The placing of the back-filling and the final keying of the arch may be left for some time after the rest of the lining is done, and the two gangs will not interfere with each other.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

1. A rib to be used in the construction of tunnel linings composed of sections in which the joints are in the main radial so that they will form a self supporting arch, but having one or more of the joints making an angle with the radial plane, and means for locking together the sections on either side of this joint, substantially as shown and described. 2. A rib to be used in the construction of tunnel linings, composed of sections in which the joints are in the main radial so as to act as an arch, but having one or more of the joints at such an angle with the radius that one of the sections adjoining may be withdrawn toward the center, and means for locking and unlocking the sections at this joint at will, substantially as shown and described. 3. A rib to be used in the construction of tunnel linings, composed of sections which, up to the springing of the arch, are, upon their outer surface, shaped to fit the inner surface of the lining, and above this point are, upon their outer surface, shaped to a contour parallel to the inner surface of the lining, and sufficiently smaller to just accommodate the lagging between, the joints between the sections being radial and such that they will act as an arch, except those at the springing of the arch, which are shaped so that one of the sections adjoining may be withdrawn toward the center, and means for locking and unlocking the sections at these joints at will, substantially as shown and described.

JAMES MONAMARA.

Witnesses:

J. LEE, I. D. MGCUTCHEON. 

